1. Field of the Invention
This application is directed generally to wireless communications systems. More particularly, but not exclusively, the application is related to methods and apparatus for generation and use of reference signals in LTE communications systems.
2. Relevant Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, video and the like. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems and other orthogonal frequency division multiple access (OFDMA) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals (also know as user equipments or UEs). Each terminal communicates with one or more base stations via transmissions on forward and reverse links. The forward link (also referred to as a downlink) refers to the communication link from the base stations (also known as access points or APs) to the terminals, and the reverse link (also referred to as an uplink) refers to the communication link from the terminals to the base stations. These communication links may be established via a single-in-single-out, single-in-multiple out, multiple-in-single-out or a multiple-in-multiple-out (MIMO) system. In MIMO systems, multiple antennas are used in both transmitters and receivers to improve communications performance without requiring additional transmit power or bandwidth. Next generation systems such as Long Term Evolution (LTE) allow for use of MIMO technology for enhanced performance and data throughput.